Conney and his team were able to confirm their hypothesis that caffeine, when consumed or applied to the skin, works by inhibiting ATR. Now they say more studies are needed to see how it may work on humans.

"We want to see whether caffeine has an effect in people when you give it topically," he says.

"Caffeine might become a weapon in prevention because it inhibits ATR and also acts as a sunscreen and directly absorbs damaging UV light."

Covering up still best protection

Manager of SunSmart Victoria, Sue Heward, says "there definitely needs to be a lot more work before we would be recommending swapping sunscreen, hats, sunglasses for drinking more coffee."

She says the study's finding doesn't mean people who drink coffee can ditch the sunhat or sunscreen.

"No. While the study showed that in genetically altered mice they were initially able to fend off non-melanoma skin cancer when exposed to UV, by the end of the study period all the mice developed tumours."

Heward says the best way to prevent skin cancer is to wear "protective clothing, broad spectrum, water-resistant SPF30+ sunscreen, a big hat, find some shade if possible and sunglasses."

According to SunSmart Victoria statistics, 1830 Australians die from skin cancer each year.

"Melanoma incidence rates in Australia and New Zealand are between two and five times as high as those found in Canada, the United States and the United Kingdom," says Heward.

"Overall, melanoma is the fourth most common cancer in Australia - behind prostate, colorectal, and breast cancer - with over 10,300 new cases diagnosed each year."

Non-melanoma types of skin cancer, including basal cell and squamous cell types, are the most commonly diagnosed and are often treatable if detected early.

Previous studies have shown coffee drinkers tend to have fewer incidences of breast, uterine, prostate and colon cancers, but the beneficial effects are not seen in people who drink decaffeinated coffee.